102 research outputs found
Micro protocol engineering for unstructured carriers: On the embedding of steganographic control protocols into audio transmissions
Network steganography conceals the transfer of sensitive information within
unobtrusive data in computer networks. So-called micro protocols are
communication protocols placed within the payload of a network steganographic
transfer. They enrich this transfer with features such as reliability, dynamic
overlay routing, or performance optimization --- just to mention a few. We
present different design approaches for the embedding of hidden channels with
micro protocols in digitized audio signals under consideration of different
requirements. On the basis of experimental results, our design approaches are
compared, and introduced into a protocol engineering approach for micro
protocols.Comment: 20 pages, 7 figures, 4 table
Covert voice over internet protocol communications with packet loss based on fractal interpolation
The last few years have witnessed an explosive growth in the research of information hiding in multimedia objects, but few studies have taken into account packet loss in multimedia networks. As one of the most popular real-time services in the Internet, Voice over Internet Protocol (VoIP) contributes to a large part of network traffic for its advantages of real time, high flow, and low cost. So packet loss is inevitable in multimedia networks and affects the performance of VoIP communications. In this study, a fractal-based VoIP steganographic approach was proposed to realise covert VoIP communications in the presence of packet loss. In the proposed scheme, secret data to be hidden were divided into blocks after being encrypted with the block cipher, and each block of the secret data was then embedded into VoIP streaming packets. The VoIP packets went through a packet loss system based on Gilbert model which simulates a real network situation. And a prediction model based on fractal interpolation was built to decide whether a VoIP packet was suitable for data hiding. The experimental results indicated that the speech quality degradation increased with the escalating packet-loss level. The average variance of speech quality metrics (PESQ score) between the "no-embedding" speech samples and the “with-embedding” stego-speech samples was about 0.717, and the variances narrowed with the increasing packet-loss level. Both the average PESQ scores and the SNR values of stego-speech samples and the data retrieving rates had almost the same varying trends when the packet-loss level increased, indicating that the success rate of the fractal prediction model played an important role in the performance of covert VoIP communications
Security of Streaming Media Communications with Logistic Map and Self-Adaptive Detection-Based Steganography
Voice over IP (VoIP) is finding its way into several applications, but its security concerns still remain. This paper
shows how a new self-adaptive steganographic method can ensure the security of covert VoIP communications over the
Internet. In this study an Active Voice Period Detection algorithm is devised for PCM codec to detect whether a VoIP packet
carries active or inactive voice data, and the data embedding location in a VoIP stream is chosen randomly according to random
sequences generated from a logistic chaotic map. The initial parameters of the chaotic map and the selection of where to
embed the message are negotiated between the communicating parties. Steganography experiments on active and inactive
voice periods were carried out using a VoIP communications system. Performance evaluation and security analysis indicates
that the proposed VoIP steganographic scheme can withstand statistical detection, and achieve secure real-time covert
communications with high speech quality and negligible signal distortion
Multi-Level Steganography: Improving Hidden Communication in Networks
The paper presents Multi-Level Steganography (MLS), which defines a new
concept for hidden communication in telecommunication networks. In MLS, at
least two steganographic methods are utilised simultaneously, in such a way
that one method (called the upper-level) serves as a carrier for the second one
(called the lower-level). Such a relationship between two (or more) information
hiding solutions has several potential benefits. The most important is that the
lower-level method steganographic bandwidth can be utilised to make the
steganogram unreadable even after the detection of the upper-level method:
e.g., it can carry a cryptographic key that deciphers the steganogram carried
by the upper-level one. It can also be used to provide the steganogram with
integrity. Another important benefit is that the lower-layer method may be used
as a signalling channel in which to exchange information that affects the way
that the upper-level method functions, thus possibly making the steganographic
communication harder to detect. The prototype of MLS for IP networks was also
developed, and the experimental results are included in this paper.Comment: 18 pages, 13 figure
Blindspot: Indistinguishable Anonymous Communications
Communication anonymity is a key requirement for individuals under targeted
surveillance. Practical anonymous communications also require
indistinguishability - an adversary should be unable to distinguish between
anonymised and non-anonymised traffic for a given user. We propose Blindspot, a
design for high-latency anonymous communications that offers
indistinguishability and unobservability under a (qualified) global active
adversary. Blindspot creates anonymous routes between sender-receiver pairs by
subliminally encoding messages within the pre-existing communication behaviour
of users within a social network. Specifically, the organic image sharing
behaviour of users. Thus channel bandwidth depends on the intensity of image
sharing behaviour of users along a route. A major challenge we successfully
overcome is that routing must be accomplished in the face of significant
restrictions - channel bandwidth is stochastic. We show that conventional
social network routing strategies do not work. To solve this problem, we
propose a novel routing algorithm. We evaluate Blindspot using a real-world
dataset. We find that it delivers reasonable results for applications requiring
low-volume unobservable communication.Comment: 13 Page
Secure covert communications over streaming media using dynamic steganography
Streaming technologies such as VoIP are widely embedded into commercial and industrial applications, so it is imperative to address data security issues before the problems get really serious. This thesis describes a theoretical and experimental investigation of secure covert communications over streaming media using dynamic steganography. A covert VoIP communications system was developed in C++ to enable the implementation of the work being carried out.
A new information theoretical model of secure covert communications over streaming media was constructed to depict the security scenarios in streaming media-based steganographic systems with passive attacks. The model involves a stochastic process that models an information source for covert VoIP communications and the theory of hypothesis testing that analyses the adversary‘s detection performance.
The potential of hardware-based true random key generation and chaotic interval selection for innovative applications in covert VoIP communications was explored. Using the read time stamp counter of CPU as an entropy source was designed to generate true random numbers as secret keys for streaming media steganography. A novel interval selection algorithm was devised to choose randomly data embedding locations in VoIP streams using random sequences generated from achaotic process.
A dynamic key updating and transmission based steganographic algorithm that includes a one-way cryptographical accumulator integrated into dynamic key exchange for covert VoIP communications, was devised to provide secure key exchange for covert communications over streaming media. The discrete logarithm problem in mathematics and steganalysis using t-test revealed the algorithm has the advantage of being the most solid method of key distribution over a public channel.
The effectiveness of the new steganographic algorithm for covert communications over streaming media was examined by means of security analysis, steganalysis using non parameter Mann-Whitney-Wilcoxon statistical testing, and performance and robustness measurements. The algorithm achieved the average data embedding rate of 800 bps, comparable to other related algorithms. The results indicated that the algorithm has no or little impact on real-time VoIP communications in terms of speech quality (< 5% change in PESQ with hidden data), signal distortion (6% change in SNR after steganography) and imperceptibility, and it is more secure and effective in addressing the security problems than other related algorithms
Covert Voice over Internet Protocol communications based on spatial model
This paper presents a new spatial steganography model for covert communications over Voice over Internet Protocol (VoIP), providing a solution to the issue of increasing the capacity of covert VoIP channels without compromising the imperceptibility of the channels. Drawing from Orthogonal Modulation Theory in communications, the model introduced two concepts, orthogonal data hiding features and data hiding vectors, to covert VoIP communications. By taking into account the variation characteristics of VoIP audio streams in the time domain, a hiding vector negotiation mechanism was suggested to achieve dynamic self-adaptive ste-ganography in media streams. Experimental results on VoIP steganography show that the pro-posed steganographic method effectively depicted the spatial and temporal characteristics of VoIP audio streams, and enhanced robustness against detection of steganalysis tools, thereby improving the security of covert VoIP communications
Non—cryptographic methods for improving real time transmission security and integrity
In this paper we present a few non cryptographic methods for improving the security, integrity
and reliability of real time services. The methods presented in this paper apply to real time
transmitting systems, which are based on the Peer-to-Peer (P2P) model. A basic idea of
the first technique is to use agents for detecting steganographic content in packet headers,
so packets with suspicious entries in the IP header fields will be blocked or the fields will be
erased. The two other presented techniques are based on reputation and trust systems, so
trust and reputation basic definitions, types and modelling methods are shown. Also a simple
design scheme of using these mechanisms in a P2P real-time data transmitting infrastructure
is presented. Additionally, we describe an idea of path selecting technique, which can be used
to avoid paths that are susceptible to eavesdropping
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